Poly(cyclohexylenedimethylene terephthalate) copolyester molding compositions

ABSTRACT

This invention relates to a molded object prepared from a copolyester having an inherent viscosity of 0.4 to 1.1 dL/g, 
     wherein the acid component comprises repeat units from 90 to 40 mole % terephthalic acid and from 10 to 60 mole % of one or more additional dibasic acids selected from the group consisting of isophthalic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, and stilbenedicarboxylic acid; 
     wherein the glycol component comprises repeat units from 1,4-cyclohexanedimethanol.

This is a continuation application under 37 CFR 1.60 of priorapplication Ser. No. 08/531,495 filed on Sep. 21, 1995, now U.S. Pat.No. 5,633,340, of Douglas C. Hoffman, Thomas J. Pecorini, James P.Dickerson, Joseph A. Deloach, "IMPROVED POLYESTER MOLDING COMPOSITIONS".

This invention relates to certain molded objects comprisingpoly(1,4-cyclohexylenedimethylene terephthalate) copolyesters which haveimproved toughness, clarity and stress crack resistance.

BACKGROUND OF THE INVENTION

Various polymeric materials have been widely used over the past 60 yearsfor molding toothbrushes, tool handles, windshield scrapers, steeringwheels, hair brushes, cutlery, eyeglass frames and the like. In many ofthese applications, the molded part must be clear, tough, impactresistant, stress crack resistant, hydrolysis resistant as well ashaving a pleasing feel and appearance.

Plasticized cellulose acetate propionate (CAP) compositions have beenused successfully in the past for toothbrush handles. Such compositionshave good clarity, sparkle and overall appearance. However, designchanges in toothbrush handles to increase the bristle density has led tocracking in certain brushes. The cracks which occur during bristleinsertion are a result of insufficient weld-line strength. Increasedplasticizer concentrations improve the weld-line strength but this leadsto decreased stiffness which can result in inadequate bristle retention.

Certain rigid polyurethane materials have been evaluated in thisapplication but this polymer is difficult to mold, and the urethanelinkages in the polymer chain can hydrolyze in the presence of moistureduring molding.

Polyester materials such as poly(ethylene terephthalate) (PET) andpoly(1,4-cyclohexylenedimethylene terephthalate) (PCT) have manydesirable properties for molded parts but these polymers are readilycrystallizable and provide hazy or opaque objects when molded in thickparts. Modification of PET polymers with high levels of glycolcomponents other than ethylene glycol provide clear, tough molded partsbut they tend to stress crack in the presence of certain toothpastesolutions containing mint oil.

For example, U.S. Pat. No. 2,901,466 (1959) assigned to Eastman KodakCompany describes a wide range of linear polyesters and polyesteramidesderived from 1,4-cyclohexanedimethanol (CHDM). Many of the compositionsare readily crystallizable and molded parts are hazy or opaque. Thus,they are not suitable for clear, molded objects.

There is a need in the art, therefore, for molding compositions whichhave visual clarity and which have improved molding and physicalproperty requirements.

SUMMARY OF THE INVENTION

This invention relates to molded objects prepared from a copolyesterhaving an inherent viscosity of 0.4 to 1.1 dL/g,

wherein the acid component comprises repeat units from 90 to 40 mole %terephthalic acid and from 10 to 60 mole % of one or more additionaldibasic acids selected from the group consisting of isophthalic acid,cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid,diphenyldicarboxylic acid, and stilbenedicarboxylic acid; and, P1wherein the glycol component comprises repeat units from1,4-cyclohexanedimethanol.

These molded objects have the advantage of having improved clarity andstress crack resistance. They also have good physical propertiesincluding strength, stiffness, impact resistance and hydrolysisresistance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1--illustrates the molded plaques used to determine chemicalresistance

FIG. 2--illustrates the testing apparatus used to determine stress crackresistance

DESCRIPTION OF THE INVENTION

It has been found that certain PCT copolyesters are highly suitable formolding clear, tough, stress crack resistant parts.

The molded objects are prepared from a copolyester having an inherentviscosity of 0.4 to 1.1 dL/g,

where the acid component comprises repeat units from 90 to 40 mole %,preferably 85 to 52 mole %, more preferably, 83 to 52 mole %terephthalic acid and from 10 to 60 mole %, preferably 15 to 48 mole,preferably 17 to 48 mole %, of one or more additional dibasic acidsselected from the group consisting of isophthalic acid,cyclohexanedicarboxylic acid, naphthalenedicarboxylic acid,diphenyldicarboxylic acid, and stilbenedicarboxylic acid;

where the glycol component comprises repeat units from1,4-cyclohexanedimethanol, preferably 80 to 100 mole %1,4-cyclohexanedimethanol, more preferably, 85 to 100 mole %, even morepreferably 90 to 100 mole %, and even more preferably 95 to 100 mole %.

When using the cyclohexanedicarboxylic acids, they may be in the cis ortrans forms or as cis/trans isomer mixtures. The lower alkyl esters,such as the methyl esters, may be used instead of the dibasic acids inpreparing the molding compositions of this invention.

When cyclohexanedicarboxylic acid is used, 1,3- and1,4-cyclohexanedicarboxylic acid are preferred. Whennaphthalenedicarboxylic acid is used, 2,6-, 2,7-, 1,4- and1,5-naphthalenedicarboxylic acid are preferred.

The molded objects of the invention, may comprise up to 10 mole % ofeven further additional dibasic acids. These dibasic acids may beselected from one or more of the group consisting of aromaticdicarboxylic acids, aliphatic dicarboxylic acids, and cycloaliphaticdicarboxylic acids, each preferably having 4 to 40 carbon atoms. Morespecifically, these additional dibasic acids can be selected from one ormore of the group consisting of phthalic acid, cyclohexanediacetic acid,succinic acid, glutaric acid, adipic acid, azelaic acid, sebacic acid,isophthalic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylicacid, diphenyldicarboxylic acid, and stilbenedicarboxylic acid.

Preferred additional carboxylic acids are selected from the groupconsisting of isophthalic acid, cyclohexanedicarboxylic acid,naphthalenedicarboxylic acid, diphenyldicarboxylic acid, andstilbenedicarboxylic acid. Even more preferred additional dibasic acidsinclude isophthalic acid, cyclohexanedicarboxylic acid andnaphthalenedicarboxylic acid.

The glycol component may contain up to 20 mole % of one or moreadditional aliphatic or alicyclic glycols, preferably containing 2 to 20carbon atoms. These additional glycols may be selected from the groupconsisting of ethylene glycol, diethylene glycol, triethylene glycol,propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol andtetramethylcyclobutanediol. Ethylene glycol is particularly preferred.

Very small amounts (less than 1.5 mole %) of certain branching agentssuch as trimellitic anhydride, trimellitic acid, pyromelliticdianhydride, trimesic acid, hemimellitic acid, glycerol,trimethylolpropane, pentaerythritol, 1,2,4-butanetriol,1,2,6-hexanetriol, sorbitol, 1,1,4,4-tetrakis(hydroxymethyl)cyclohexane,dipentaerythritol and the like may be used.

The copolyesters of this invention are readily prepared using melt phaseor solid state polycondensation procedures well known in the art. Theymay be made by batch or continuous processes. Examples of theseprocesses can be found in U.S. Pat. Nos. 4,256,861, 4,539,390, and2,901,466 and include preparation by direct condensation or by esterinterchange.

Specifically, the polymers of this invention may be prepared accordingto the methods described in U.S. Pat. No. 2,901,466. However, thepreparation of the polymers of this invention is not particularlylimited to the method described in U.S. Pat. No. 2,901,466. This patentdiscloses interchange reactions as well as polymerization build-upprocesses. Briefly, a typical procedure consists of at least twodistinct stages; the first stage, known as ester-interchange oresterification, is conducted under an inert atmosphere at a temperatureof 150° to 250° C. for 0.5 to 8 hours, preferably from 180° to 240° C.for 1 to 4 hours. The glycols, depending on their reactivities and thespecific experimental conditions employed, are commonly used in molarexcesses of 1.05-2.5 per total moles of acid-functional monomers. Thesecond stage, referred to as polycondensation, is conducted underreduced pressure at a temperature of 230° to 350° C., preferably 265° to325° C., and more preferably 270° to 300° C. for 0.1 to 6 hours,preferably 0.25 to 2 hours. Stirring or appropriate conditions are usedin both stages to ensure adequate heat transfer and surface renewal ofthe reaction mixture. The reactions of both stages are facilitated byappropriate catalysts, especially those well-known in the art, such asalkoxy titanium compounds, alkali metal hydroxides and alcoholates,salts of organic carboxylic acids, alkyl tin compounds, metal oxides,and so forth.

Suitable copolyesters will have inherent viscosity (I.V.) values ofabout 0.4 to about 1.1 dL/g. Such values are obtained in a 60/40phenol/tetrachlorethane solution containing 0.5 grams (g) of polymer in100 milliliters (mL) of solution. It is preferred that the copolyestershave I.V. values of at least 0.5 dL/g.

Preferred copolyesters must have glass transition temperatures (Tg) ofat least 70° C. as determined by Differential Scanning Calorimetry (DSC)and a crystallization half-time of at least 1 minute as measured by asmall angle laser light scattering technique.

The technique for determining the crystallization haze half-timesconsists primarily in following the increase in depolarization ofplane-polarized light by the polyester. The method used in thisinvention is primarily that shown in "A New Method for Following RapidRates of Crystallization", I. Poly (hexamethylene adipamide), J. H.Magill, Polymer, Vol. 2, page 221-233 (1961) with the exception thatMagill uses a polarizing microscope as the source of light andlight-collection lenses. In measuring the crystallization half-times ofthe present invention, a helium-neon laser with a small angle lightscattering technique (SALS)! was used as was shown by Adams and Stein inJ. Polymer Sci. A2, Vol. 6 (1962).

Crystallization half-times are measured at the time in which thetransmitted intensity is half of the maximum intensity achieved.

The method used is generally as follows:

(1) Melt the sample to remove existing crystallinity;

(2) Crystallize the sample polyester at a pre-determined temperature;

(3) Record the transmitted light intensity plotted versus time;

(4) Find the time at which the transmitted intensity is half of themaximum intensity achieved.

The above procedure is repeated at different temperatures until aminimum value for the crystallization half-time can be measured."Minimum value" refers to the lowest measurable point on a curve plottedusing the temperature data and corresponding crystallization half-timedata.

The term "crystallization haze half-time as measured from the meltphase" as defined herein is the procedure as describe above.

It is preferred that the molded objects of the invention have acrystallization haze half-time of greater than 1 minute, preferablygreater than 3 minutes, and more preferably greater than 5 minutes.

When the molded objects of the invention have crystallization hazehalf-times as described, they are generally visually clear for regionsof a molded object having a thickness of from 1 to 11.5 mm, preferably 3to 11.5."

It is also preferable that molded objects prepared from the blends ofthe invention have a diffuse transmittance value of less than about 60%,more preferably, less than about 40%, and more preferably, less thanabout 20% as determined by ASTM Method D1003. When the diffusetransmittance value is less than about 60%, the molded objects arevisually clear.

Also, the molded objects of the invention demonstrate improved stresscracking resistance as determined for test specimens which are 0.32centimeters thick under a flexural load with 1.4% strain and with 2.7%strain and as demonstrated more fully in the following Examples.

This stress cracking resistance testing is preferably performed in thepresence of a flavorant. More preferably, the flavorant is a mint oil.Of the possible mint oils, it is preferable that the mint oil is eitherpeppermint oil or spearmint oil.

The stress cracking resistance measurements used in the invention arealso preferably performed in the presence of a toothpaste solutioncomprising water and a toothpaste containing greater than 0.6 weight %mint oil or, more specifically, in the presence of peppermint oildirectly as described more fully in the following

EXAMPLES

Other ingredients may be used in the toothpaste solutions includingglycerine, sodium bicarbonate, water, hydrated silicate, polyethyleneglycol, sodium laural sulfate, sodium laural sarcosinate, sodiumpyrophosphates, sodium phosphates, sorbitol, sodium benzoate, sodiumsaccharin, xantham gum, cellulose gum, flavorants, sodium saccharin,FD&C blue #1 and FD&C yellow #10, FD&C red 30, 1-hydroxy-2-propanone,3-octanol, 4-methyl-l-(l-methylethyl)cyclohexene, pulegone, dodecanol,3-phenyl-2-propenal, dodecanol, eugenol and titanium dioxide.

Flavorants useful in performing the tests of the invention includepeppermint oil, curly mint oil, anise oil, Japanese anise oil, carawayoil, eucalyptus oil, fennel oil, cinnamon oil, clove oil, geranium oil,sage oil, pimento oil, thyme oil, and majoram oil.

Mint oil may contain several ingredients including, but not limited to:limonene, cineole, menthone, menthol, and carvone.

The copolyesters may be used in clear form or they may be colored orpigmented with additives or copolymerizable colorants. Typically usefulcopolymerizable colorants are described in U.S. Pat. Nos. 5,030,708(1991), 5,102,980 (1992) and 5,194,571 (1993) all assigned to EastmanKodak Company, incorporated herein by reference.

Other additives such as stabilizers, antioxidants, mold release agents,fillers and the like may also be used if desired. Polymer blends may beused.

The copolyesters of this invention are easy to mold into desired shapessuch as toothbrush handles, hair brush handles, ice scrapers, cutlery orcutlery handles, tool handles, automotive steering wheels, eyeglassframes and the like. This invention can be further illustrated by thefollowing examples of preferred embodiments thereof, although it will beunderstood that these examples are included merely for purposes ofillustration and are not intended to limit the scope of the inventionunless otherwise specifically indicated. The starting materials arecommercially available unless otherwise indicated. Percentages are byweight unless otherwise stated.

I. PREPARATION OF COPOLYESTERS AND MOLDED OBJECTS Example 1 ComparativePreparation of Copolyesters Containing Terephthalate, Ethylene Glycoland 3 Mole % 1,4-Cyclohexanedimethanol

A 5000 mL stainless steel reactor equipped with an agitator shaft,nitrogen inlet, and an outlet to allow for removal of volatile materialswas charged with 679.7 grams (3.5 mole) of dimethyl terephthalate (DMT),427.8 grams (6.9 mole) of ethylene glycol (EG), 16.4 grams (0.11 mole)of 1,4-cyclohexanedimethanol (CHDM) (70 % trans isomer/30 % cis isomer)and 1.35 mL of a 3.30% (w/v) solution of titanium (IV) isopropoxide inn-butanol. The reactor was purged with nitrogen and heated to 200° C.under a slow nitrogen sweep with agitation and held for one hour. Thereactor temperature was raised to 220° C. and held for two hours. Thetemperature was raised to 280° C. and the nitrogen purge was removed anda vacuum was applied such that a vacuum of <0.5 mm was attained over a30 minute period. The reactor was stirred under vacuum for one hour. Thevacuum was then displaced with a nitrogen atmosphere and the polymer wasextruded through an opening in the bottom of the reactor. The extrudedrod was cooled in an 5° C.. water bath and pelletized. The recoveredpolymer pellets had an inherent viscosity of 0.70 deciliters (dL)/gaccording to ASTM D3835-79. The diol component of the polymer consistedof 96 mole % EG, 3 mole % CHDM and 1 mole % diethylene glycol (DEG) asmeasured by gas chromatography on a hydrolyzed sample. A glasstransition temperature (T_(g)) of 78° C. and a melting point (T_(m)) of248° C. were measured by DSC (differential scanning calorimetry)analysis. The crystallization haze half-time as measured from the meltphase was 0.8 minutes. The sample was dried at 150° C. in a dehumidifierdrier for about 4 hours and injection molded into clear plaques thatwere 7.5 centimeters (cm) square and 0.32 cm thick. Locatedapproximately 1 cm from the plaque edge was an area 1.cm by 0.6 cm whichcontains twelve holes approximately 0.1 cm in diameter as shown inFIG. 1. This area of the plaque was used to simulate the head of atoothbrush into which bristles would be inserted.

Example 2 Comparative Preparation of Copolyester ContainingTerephthalate, EG and 31 Mole % CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 679.5 grams(3.5 mole) DMT, 365.6 grams (5.9 mole) EG, 160.4 grams (1.1 mole) CHDMand 2.05 mL of a 3.30% (w/v) solution of titanium isopropoxide inn-butanol. The diol interchange step was conducted at 200° C. for onehour and at 210° C. for two hours. The polycondensation step wasconducted at a vacuum of 0.5 mm Hg for one hour. The polymer wasextruded from the bottom of the reactor. The extruded rod was cooled inan 5° C. water bath and pelletized. The recovered polymer pellets had aninherent viscosity of 0.74 dL/g. The diol component of the polymerconsisted of 68 mole % EG, 31 mole % CHDM and 1 mole % DEG. Theamorphous copolymer possessed a T_(g) of 80° C. as determined by DSCanalysis. The crystallization haze half-time as measured from the meltphase was greater than 1 hour. The sample was dried at 65° C. in adehumidifier drier for about 16 hours. It was injection molded intoclear specimens set forth in Example 1.

Example 3 Comparative Preparation of Copolyester ContainingTerephthalate, EG and 62 Mole % CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 679.7 grams(3.5 mole) DMT, 305.6 grams (4.9 mole) EG, 302.5 grams (2.1 mole) CHDMand 2.06 mL of a 3.30% (w/v) solution of titanium isopropoxide inn-butanol. The diol interchange step was conducted at 200° C. for onehour and at 210° C. for two hours. The polycondensation step wasconducted at a vacuum of 0.5 mm Hg for 45 minutes. The polymer wasextruded from the bottom of the reactor. The extruded rod was cooled inan 5° C. water bath and pelletized. The recovered polymer pellets had aninherent viscosity of 0.72 dL/g. The diol component of the polymerconsisted of 37 mole % EG, 62 mole % CHDM and 1 mole % DEG. A T_(g) of82° C. and a T_(m) of 225° C. were obtained for the copolymer by DSCanalysis. The crystallization haze half-time as measure from the meltphase was 28 minutes. The sample was dried at 65° C. in a dehumidifierdrier for about 16 hours and injection molded into clear specimens setforth in Example 1.

Example 4 Comparative Preparation of Copolyester ContainingTerephthalate. EG and 81 Mole % CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 679.2 grams(3.5 mole) DMT, 248.1 grams (4.0 mole) EG, 432.9 grams (3.0 mole) CHDMand 2.38 mL of a 3.30% (w/v) solution of titanium isopropoxide inn-butanol. The diol interchange step was conducted at 200° C. for onehour and at 210° C. for two hours. The polycondensation step wasconducted at a vacuum of 0.5 mm Hg for 40 minutes. The polymer wasextruded from the bottom of the reactor, cooled in an 5° C. water bathand pelletized. The recovered polymer pellets had an inherent viscosityof 0.76 dL/g and the diol component of the polymer consisted of 18 mole% EG, 81 mole % CHDM and 1 mole % DEG. A T_(g) of 87° C. and a T_(m) of257° C. were obtained for the copolymer by DSC analysis. Thecrystallization haze half-time as measured from the melt phase was 3minutes. The sample was dried at 150° C. in a dehumidifier drier forabout 4 hours and injection molded into clear specimens set forth inExample 1.

Example 5 Comparative Preparation of Copolyester Containing 95 Mole %Terephthalate, 5 Mole % Isophthalate and CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 645.2 grams(3.3 mole) DMT, 34.1 grams (0.2 mole) dimethyl isophthalate (DMI), 555.7grams (3.9 mole) CHDM and 2.68 mL of a 3.30% (w/v) solution of titaniumisopropoxide in n-butanol. The reactor was purged with nitrogen andheated to 300° C. under a slow nitrogen sweep with agitation. Thereactor temperature was held for 30 minutes and then the nitrogen purgewas removed and a vacuum was applied such that a vacuum of <0.5 mm Hgwas attained over a 30 minute period. The vacuum and temperature washeld for 50 minutes. The polymer was extruded from the bottom of thereactor. The extruded rod was cooled in an 5° C. water bath andpelletized. The recovered polymer pellets had an inherent viscosity of0.78 dL/g and the polymer consisted of 95 mole % terephthalate and 5mole % isophthalate as measured by ¹ H NMR. A T_(g) of 92° C. and aT_(m) of 287° C. were obtained for the copolymer by DSC analysis. Thecrystallization haze half-time as measured from the melt phase was 0.5minutes. The sample was dried at 150° C. in a dehumidifier drier forabout 4 hours and injection molded into clear specimens set forth inExample 1.

Example 6 Example of the Invention Preparation of Copolyester Containing83 Mole % Terephthalate, 17 Mole % Isophthalate and CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 577.3 grams(3.0 mole) DMT, 101.9 grams (0.5 mole) DMI, 565.4 grams (3.9 mole) CHDMand 2.67 mL of a 3.30% (w/v) solution of titanium isopropoxide inn-butanol. The reactor was purged with nitrogen and heated to 290° C.under a slow nitrogen sweep with agitation. The reactor temperature washeld for 30 minutes and then the nitrogen purge was removed and a vacuumwas applied such that a vacuum of <0.5 mm Hg was attained over a 30minute period. The vacuum and temperature was held for 43 minutes. Thepolymer was extruded from the bottom of the reactor, cooled in an 5° C.water bath and pelletized. The recovered polymer pellets had an inherentviscosity of 0.70 dL/g and the polymer consisted of 83 mole %terephthalate and 17 mole % isophthalate as measured by ¹ H NMR. A T_(g)of 89° C. and a T_(m) of 262° C. were obtained for the copolymer by DSCanalysis. The crystallization haze half-time as measured from the meltphase was 1.5 minutes. The sample was dried at 150° C. in a dehumidifierdrier for about 4 hours and injection molded into clear specimens setforth in Example 1.

Example 7 Example of the Invention Preparation of Copolyester Containing70 Mole % Terephthalate, 30 Mole % Isophthalate and CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 476.3 grams(2.5 mole) DMT, 204.1 grams (1.0 mole) DMI, 555.8 grams (3.9 mole) CHDMand 2.67 mL of a 3.30% (w/v) solution of titanium isopropoxide inn-butanol. The reactor was purged with nitrogen and heated to 290° C.under a slow nitrogen sweep with agitation. The reactor temperature washeld for 30 minutes and then the nitrogen purge was removed and a vacuumwas applied such that a vacuum of <0.5 mm Hg was attained over a 30minute period. The vacuum and temperature was held for 53 minutes. Thepolymer was extruded from the bottom of the reactor. The extruded rodwas cooled in an 5° C. water bath and pelletized. The recovered polymerpellets had an inherent viscosity of 0.70 dL/g and the polymer consistedof 70 mole % terephthalate and 30 mole % isophthalate as measured by ¹ HNMR. An amorphous polymer was recovered that had a Tg of 87° C. asmeasured by DSC. The crystallization haze half-time as measured from themelt phase was 6.8 minutes. The sample was dried at 65° C. in adehumidifier drier for about 4 hours and injection molded into clearspecimens set forth in Example 1.

Example 8 Example of the Invention Preparation of Copolyester Containing61 Mole % Terephthalate, 39 Mole % 1,4-Cyclohexanedicarboxylate and CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 404.7 grams(2.1 mole) DMT, 243.6 grams (1.4 mole) of dimethyl1,4-cyclohexanedicarboxylate (DMCD) (35% trans isomer/65% cis isomer),580.4 grams (4.03 mole) of CHDM and 2.65 mL of a 3.30% (w/v) solution oftitanium isopropoxide in n-butanol. The reactor was purged with nitrogenand heated to 220° C. for 60 minutes under a slow nitrogen sweep withsufficient agitation. After raising the temperature to 290° C. thenitrogen purge was removed and a vacuum was applied such that a vacuumof <0.5 mm Hg was attained in 30 min. The vacuum and temperature washeld for 120 minutes to perform the polycondensation. The vacuum wasthen displaced with a nitrogen atmosphere and the polymer was drainedfrom the bottom of the reactor, cooled in an 5° C. water bath andpelletized. An inherent viscosity of 0.70 dL/g was determined for therecovered polymer. The polymer contained 61 mole % terephthalate and 39mole % 1,4-cyclohexanedicarboxylate (51% trans isomer/49% cis isomer) asmeasured by ¹ H NMR. A T_(g) of 72° C. and a T_(m) of 223° C. wereobtained for the copolymer by DSC analysis. The crystallization hazehalf-time as measured from the melt phase was 15 minutes. The sample wasdried at 65° C. in a dehumidifier drier for about 4 hours and injectionmolded into clear specimens set forth in Example 1.

Example 9 Example of the Invention Preparation of Copolyester Containing52 Mole % Terephthalate, 48 Mole % 1,4-Cyclohexanedicarboxylate and CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 404.7 grams(2.1 mole) of dimethyl terephthalate (DMT), 243.6 grams (1.4 mole) ofdimethyl 1,4-cyclohexanedicarboxylate (95% trans isomer/5% cis isomer),580.4 grams (4.03 mole) of CHDM and 2.68 mL of a 3.30% (w/v) solution oftitanium isopropoxide in n-butanol. The reactor was purged with nitrogenand heated to 290° C. under a slow nitrogen sweep with agitation. Thereactor temperature was held for 30 minutes and then the nitrogen purgewas removed and a vacuum was applied such that a vacuum of <0.5 mm wasattained over a 30 minute period. The vacuum and temperature was heldfor 53 minutes. The polymer was extruded from the bottom of the reactorthrough an orifice. The extruded rod was cooled in an 5° C. water bathand pelletized. An inherent viscosity of 0.74 dL/g was determined forthe recovered polymer. The polymer contained 52 mole % terephthalate and48 mole % 1,4-cyclohexanedicarboxylate (88% trans isomer/12% cis isomer)as measured by ¹ H NMR. A glass transition temperature T_(g) of 78° C.and a T_(m) of 225° C. were obtained for the polymer by DSC analysis.The crystallization haze half-time as measured from the melt phase was11.5 minutes. The sample was dried at 65° C. in a dehumidifier drier forabout 4 hours and injection molded into clear specimens set forth inExample 1.

Example 10 Example of the Invention Preparation of CopolyesterContaining 70 Mole % Terephthalate, 30 Mole %2.6-Naphthalenedicarboxylate and CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 477.0 grams(2.5 mole) DMT, 203.9 grams (1.0 mole) DMI, 565.4 grams (3.9 mole) CHDMand 2.67 mL of a 3.30% (w/v) solution of titanium isopropoxide inn-butanol. The reactor was purged with nitrogen and heated to 290° C.under a slow nitrogen sweep with agitation. The reactor temperature washeld for 30 minutes and then the nitrogen purge was removed and a vacuumwas applied such that a vacuum of <0.5 mm was attained over a 30 minuteperiod. The vacuum and temperature was held for 43 minutes. The polymerwas extruded from the bottom of the reactor. The extruded rod was cooledin a 5° C. water bath and pelletized. The recovered polymer pellets hadan inherent viscosity of 0.64 dL/g and the polymer consisted of 70 mole% terephthalate and 30 mole % naphthalate as measured by ¹ H NMR. AT_(g) of 103° C. and a T_(m) of 246° C. were obtained for the polymer byDSC analysis. The crystallization haze half-time as measured from themelt phase was 9 minutes. The sample was dried at 85° C. in adehumidifier drier for about 4 hours and injection molded into clearspecimens set forth in Example 1.

Example 11 Example of the Invention Preparation of CopolyesterContaining 68 Mole % Terephthalate, 32 Mole % 1.4-Cyclohexanedicarboxylate and CHDM

The apparatus and procedure set forth in Example 1 was used. Thefollowing amounts of reactants were charged to the reactor: 461.8 grams(2.4 mole) of dimethyl terephthalate (DMT), 224.0 grams (1.1 mole) ofdimethyl 1,4-cyclohexanedicarboxylate (95% trans isomer/5% cis isomer),580.4 grams (4.03 mole) of CHDM and 2.68 mL of a 3.30% (w/v) solution oftitanium isopropoxide in n-butanol. The reactor was purged with nitrogenand heated to 290° C. under a slow nitrogen sweep with agitation. Thereactor temperature was held for 30 minutes and then the nitrogen purgewas removed and a vacuum was applied such that a vacuum of <0.5 mm wasattained over a 30 minute period. The vacuum and temperature was heldfor 50 minutes. The polymer was extruded from the bottom of the reactorthrough an orifice. The extruded rod was cooled in an 5° C. water bathand pelletized. An inherent viscosity of 0.70 dL/g was determined forthe recovered polymer. The polymer contained 68 mole % terephthalate and32 mole % 1,4-cyclohexanedicarboxylate (89% trans isomer/11% cis isomer)as measured by ¹ H NMR. A glass transition temperature T_(g) of 82° C.and a T_(m) of 245° C. were obtained for the polymer by DSC analysis.The crystallization haze half-time from the melt was 2 minutes. Thesample was dried at 65° C. in a dehumidifier drier for about 4 hours andinjection molded into clear specimens set forth in Example 1.

II. PREPARATION FOR AND PERFORMANCE OF STRESS CRACKING RESISTANCEMETHODS USING PEPPERMINT OIL AND TOOTHPASTE SOLUTION A. Preparation ofToothpaste Solution

A toothpaste solution using Toothpaste A as described in the followingTables was prepared using the following procedure. In a 500 mlcontainer, 50 grams of solid toothpaste was added 120 ml of plain tapwater. The mixture was sealed and then stirred using a magnetic stirringbar and a magnetically driven stirring plate. After a 30 minute mixingtime the dispersion was applied to the test specimens using anapplicator brush and observed. The same toothpaste solution was usedthroughout each testing cycle. The following morning the test specimensfrom Examples 1-10 were inspected and ranked on their appearance usingthe craze ranking system. Crazes are precursors to cracks which form dueto the interaction of the solvent with the polymer matrix. Crazes aresimilar to cracks, but crazes contain highly oriented fibrils of polymerwhich span its faces. Crazes are not necessarily structural defects, butoften lead to the formation of true cracks. After the ranking, the testspecimens were wetted with the toothpaste solution. The specimens werewet with the toothpaste solution 8 hours later and observed thefollowing morning.

The stress crack resistance to pepper mint oil was determined using thesame methodology as the toothpaste solution testing.

Peppermint oil has the following composition:

    ______________________________________                                        Peppermint Oil Composition                                                    Compound         Weight Percent                                               ______________________________________                                        Dimethylsulfide  0.02                                                         2 Methyl propanal                                                                              0.03                                                         3 methyl propanal                                                                              <0.01                                                        2 Methyl butanal <0.01                                                        3 Methyl butanal 0.15                                                         2 Ethyl furan    0.03                                                         trans-2,5-Diethyl THF                                                                          0.02                                                         α-Pinene   0.66                                                         Sabinene         0.42                                                         Myrcene          0.18                                                         α-Terpinene                                                                              0.34                                                         Limonene         1.33                                                         1,8 Cineole      4.80                                                         trans-Ocimene    0.03                                                         cis-Ocimene      0.31                                                         G-Terpinene      0.56                                                         trans-2-Hexenal  0.07                                                         para-Cymeme      0.10                                                         Terpeniolene     0.16                                                         Hexanol          0.13                                                         3 Octyl acetate  0.03                                                         cis-3-Hexenol    0.01                                                         3-Octanol        0.21                                                         trans-2-Hexenol  0.02                                                         Sabinene hydrate 0.80                                                         Menthone         20.48                                                        Menthofuran      1.67                                                         D-Isomenthone    2.77                                                         B-Bourbonol      0.37                                                         Neomenthylacetate                                                                              0.21                                                         Linalool         0.26                                                         cis-Sabinene hydrate                                                                           0.07                                                         Menthyl acetate  5.02                                                         Isopulegol       0.07                                                         Neoisomenthyl acetate                                                                          0.26                                                         Neomenthol       3.34                                                         β-Caryophyllene                                                                           2.13                                                         Terpinene-4-ol   0.98                                                         Neoisoisopulegol 0.03                                                         Neoisomenthol    0.78                                                         Menthol          43.18                                                        Pulegone         0.77                                                         trans-β Farenscene                                                                        0.29                                                         Isomenthol       0.19                                                         Humelene         0.03                                                         α-Terpineol                                                                              0.16                                                         Germacrene-D     2.29                                                         Piperitone       0.96                                                         Viridiflorol     0.26                                                         Eugenol          0.02                                                         Thymol           0.04                                                         ______________________________________                                    

B. Toothpaste and Peppermint Oil Resistance Testing of Molded Articles

Plaques molded from Examples 1-10 were mounted in a testing rig shown inFIG. 2. In FIG. 2 the parts labelled A are clamps to hold the testspecimen, B is the curved portion of the rig which determines the strainthe test specimens are under and C is the molded plaque under strain.The testing rig was configured such that the flexural strain on eachspecimen is 2.7%. The testing rigs were used to simulate end-useconditions such as bristle insertion. The specimens remained in thetesting rigs for 7 days and observed each day for the formation ofcrazes. A ranking system from 1-3 was used to identify the severity ofcrazing on each specimen, (visual observation codes as referred toherein). In this system, visual observation code 1 was assigned to testplaques that exhibit no change during the testing period. As theseverity of crazing increases the ranking increases in value.

Table 1 illustrates the effect of 2.7% flexural strain on the testspecimens fabricated from pellets of Examples 1-5. No effect wasobserved on all test specimens. This indicates that placement of thetest specimens in the testing apparatus does not induce crazing.

The effect of the toothpaste solution on Examples 1-5 under flexuralstrain are shown in Table 2. The data in Table 2 indicates that as theCHDM content of the copolyesters is increased relative to the EG contentthe resistance to stress cracking of the test specimen improves. At highlevels of CHDM as illustrated by Examples 4 and 5, no effect wasobserved. The same trend was observed when peppermint oil was used asthe chemical agent as shown in Table 3.

The data in Tables 2 and 3 indicate that Examples 4 and 5 have superiorresistance to stress cracking when exposed to toothpaste solution andpeppermint oil under flexural strain than Examples 1-3. Examples 3, 4and 5 were injection molded into cylindrically shaped articles that wereapproximately 20 cm in length. The diameter of each article variedbetween 5 and 11.5 mm. The molded articles prepared from Example 3 wereclear throughout. The molded articles prepared from Examples 4 and 5were not completely clear. They contained opaque sections, generally inthe area of the article with the largest diameter. This result indicatedthat the copolyesters represented by Examples 4 and 5 are resistance tostress cracking however; molded articles with thick sections ofmaterials in Examples 4 and 5 were not preferred.

In Table 4, the effect of 2.7% flexural strain on specimens fabricatedfrom Examples 6-10 is shown. The data in Table 4 indicates thatplacement of the test specimens in the testing apparatus does not inducecrazing. The data in Table 5 indicates that the plaques molded fromExamples 6-10 do not show any effect when tested under flexural strainin the presence of toothpaste solution. The data in Table 6 indicatesthat Examples 6-10 all show improved stress crack resistance topeppermint oil under flexural strain than Examples 1-3. Pellets fromExamples 6-10 were injection molded into cylindrically shaped articles20 cm long. The diameter of each article varied between 5 and 11.5 mm.The molded articles prepared from Example 6 contained opaque sectionsparticularly in the thickest sections, while the articles prepared fromExamples 7-10 were clear throughout. This result indicates that certaincopolyesters can be used to produce molded articles with thick sectionsthat have excellent clarity and are resistance to stress cracking bytoothpaste and peppermint oil.

Pellets from Example 6 were injection molded into cylindrically shapedarticles 20 cm long. The diameter of each article varied between 5 and 7mm. The molded articles were clear throughout. This result indicatesthat certain copolyesters can be used to produce molded articles thathave excellent clarity and are resistant to stress cracking bytoothpaste and peppermint oil.

                  TABLE 1                                                         ______________________________________                                        Effect of 2.7% Flexural Strain on Copolyesters Without                        Use of Toothpaste A Solution or Peppermint Oil                                Time                                                                          (hrs.)                                                                             Example 1 Example 2                                                                              Example 3                                                                             Example 4                                                                            Example 5                              ______________________________________                                        18   1         1        1       1      1                                      42   1         1        1       1      1                                      66   1         1        1       1      1                                      90   1         1        1       1      1                                      162  1         1        1       1      1                                      186  1         1        1       1      1                                      ______________________________________                                         Visual Observation Codes:                                                     1 = No effect                                                                 2 = test specimen is lightly crazed. Crazes are shallow and randomly          located                                                                       3 = test specimen is heavily crazed. Crazes are deep and randomly located

                  TABLE 2                                                         ______________________________________                                        Effect of Toothpaste A Solution on Copolyesters at 2.7%                       Flexural Strain                                                               Time                                                                          (hrs.)                                                                             Example 1 Example 2                                                                              Example 3                                                                             Example 4                                                                            Example 5                              ______________________________________                                        18   3         3        3       1      1                                      42   3         3        3       1      1                                      66   3         3        3       1      1                                      90   3         3        3       1      1                                      162  3         3        3       1      1                                      186  3         3        3       1      1                                      ______________________________________                                         Visual Observation Codes:                                                     1 = No effect                                                                 2 = test specimen is lightly crazed. Crazes are shallow and randomly          located                                                                       3 = test specimen is heavily crazed. Crazes are deep and randomly located

                  TABLE 3                                                         ______________________________________                                        Effect of Peppermint Oil on Copolyesters at 2.7% Flexural                     Strain                                                                        Time                                                                          (hrs.)                                                                             Example 1 Example 2                                                                              Example 3                                                                             Example 4                                                                            Example 5                              ______________________________________                                        2    3S        3S       3S      2      2                                      18   3S        3S       3S      2      2                                      42   3S        3S       3S      2      2                                      66   3S        3S       3S      2      2                                      90   3S        3S       3S      2      2                                      114  3S        3S       3S      2      2                                      ______________________________________                                         Visual Observation Codes:                                                     1 = No effect                                                                 2 = test specimen is lightly crazed. Crazes are shallow and randomly          located                                                                       3 = test specimen is heavily crazed. Crazes are deep and randomly located     S = test specimen swelled                                                

                  TABLE 4                                                         ______________________________________                                        Effect of 2.7% Flexural Strain on Copolyesters Without                        the Use of Toothpaste Solution or Peppermint Oil                              Time  Exam-   Exam-    Exam- Exam-  Exam- Exam-                               (hrs.)                                                                              ple 6   ple 7    ple 8 ple 9  ple 10                                                                              ple 11                              ______________________________________                                        18    1       1        1     1      1     1                                   42    1       1        1     1      1     1                                   66    1       1        1     1      1     1                                   90    1       1        1     1      1     1                                   162   1       1        1     1      1     1                                   186   1       1        1     1      1     1                                   ______________________________________                                         Visual Observation Codes:                                                     1 = No effect                                                                 2 = test specimen is lightly crazed. Crazes are shallow and randomly          located                                                                       3 = test specimen is heavily crazed. Crazes are deep and randomly located

                  TABLE 5                                                         ______________________________________                                        Effect of Toothpaste A Solution on Copolyesters at 2.7%                       Flexural Strain                                                               Time                                                                          (hrs.)                                                                             Example 6 Example 7                                                                              Example 8                                                                             Example 9                                                                            Example 10                             ______________________________________                                        19   1         1        1       1      1                                      42   1         1        1       1      1                                      66   1         1        1       1      1                                      90   1         1        1       1      1                                      162  1         1        1       1      1                                      186  1         1        1       1      1                                      ______________________________________                                         Visual Observation Codes:                                                     1 = No effect                                                                 2 = test specimen is lightly crazed. Crazes are shallow and randomly          located                                                                       5 = test specimen is heavily crazed. Crazes are deep and randomly located

                  TABLE 6                                                         ______________________________________                                        Effect of Peppermint Oil on Copolyesters at 2.7% Flexural                     Strain                                                                        Time                                                                          (hrs.)                                                                             Example 6 Example 7                                                                              Example 8                                                                             Example 9                                                                            Example 10                             ______________________________________                                        1    2         2        3S      2      2                                      22   2         2        3S      2      3                                      46   2         2        3S      2      3                                      70   2         2        3S      2      3                                      94   2         2        3S      2      3                                      118  2         2        3S      2      3                                      ______________________________________                                         Visual Observation Codes:                                                     1 = No effect                                                                 2 = test specimen is lightly crazed. Crazes are shallow and randomly          located                                                                       3 = test specimen is heavily crazed. Crazes are deep and randomly located     S = test specimen swelled                                                

Comparison of Tensile Strength of Molded Articles Before and AfterExposure to Toothpaste Solution

In Tables 7 and 8, the effect of the toothpaste solutions on retainedtensile strength are displayed. Pellets of the examples listed in thetables were molded into tensile bars of 0.32 cm thickness as per ASTMmethod D638. One sample of the bars was tested as per ASTM D638 withoutany exposure to the toothpaste solution to establish a control standard.Additional bars were held in the strain rig described in the previoussection at flexural strains of either 1.4% and 2.7%. The toothpastesolution was applied to these bars for one week as described in theprevious section. After exposure, the bars were removed from the rig andtested per ASTM D638. The ratio of tensile strength of the exposedspecimen to the tensile strength of the control standard multipliedtimes 100% is the percent retained strength. Any Example which shows aretained strength of more than 90%, preferably, more than 95%, morepreferably, more than 98%, and even more preferably, 100%, is deemed topossess sufficient chemical resistance for toothbrush applications.

The data in Table 7 confirm that Examples 1-3 possess inferior chemicalresistance after exposure to Toothpaste A. The data in Table 8 show howincreasing the flavorant level in the toothpaste affect Examples 2, 3, 6and 11. The flavorant level was determined to be the total percentage ofLimonene, Cineole, Methone, Menthol and Carvone, as determined by gaschromatography combined with mass spectroscopy. The levels of thesecomponents are also listed in Table 8. These five components are thechief compounds present in peppermint and spearmint oils. Levels ofother components are listed in Table 9.

                  TABLE 7                                                         ______________________________________                                                  Percentage of Retained Strength*                                                @ 1.4% Flexural                                                                           @ 2.7% Flexural                                       Example     Strain      Strain                                                ______________________________________                                        1           30          27                                                    2           0           0                                                     3           38          0                                                     4           98          98                                                    5           100         100                                                   6           100         100                                                   7           100         100                                                   8           100         100                                                   9           100         100                                                   10          100         100                                                   11          100         100                                                   ______________________________________                                    

                                      TABLE 8                                     __________________________________________________________________________                 Example 2                                                                           Example 3                                                                           Example 6                                                                           Example 11                                            Percent                                                                             VO Code*                                                                            VO Code*                                                                            VO Code*                                                                            VO Code*                                              By Weight                                                                           (% Retained                                                                         (% Retained                                                                         (% Retained                                                                         (% Retained                                           Flavorant                                                                           Strength)                                                                           Strength)                                                                           Strength)                                                                           Strength)                                      __________________________________________________________________________    Toothpaste A*                                                                        0.800%                                                                              3 (0%)      1 (100%)                                                                            1 (100%)                                       Toothpaste B*                                                                        0.475%                                                                              1 (97%)                                                                             2 (98%)                                                                             1 (100%)                                                                            1 (100%)                                       Toothpaste C*                                                                        0.685%                                                                              2 (81%)                                                                             2 (98%)                                                                             1 (100%)                                                                            1 (100%)                                       Toothpaste D*                                                                        0.480%                                                                              2 (67%)     1 (100%)                                                                            1 (100%)                                       Toothpaste E*                                                                        0.845%                                                                              3 (0%)                                                                              3 (0%)                                                                              1 (100%)                                                                            1 (100%)                                       Toothpaste F*                                                                        0.740%                                                                              3 (0%)      1 (100%)                                                                            1 (100%)                                       __________________________________________________________________________    Flavorant Compositions by Weight Percentages for Toothpastes A-F:                    Limonene                                                                           Cineole                                                                             Menthone                                                                           Menthol                                                                             Carvone                                                                           Total                                        __________________________________________________________________________    Toothpaste A:                                                                        <0.01                                                                              0.02  0.105                                                                              0.67  0.01                                                                              0.800                                        Toothpaste B:                                                                        0.02 <0.01 0.01 0.215 0.23                                                                              0.475                                        Toothpaste C:                                                                        <0.01                                                                              0.015 0.09 0.57  0.01                                                                              0.685                                        Toothpaste D:                                                                        0.01 <0.01 0.05 0.31  0.11                                                                              0.480                                        Toothpaste E:                                                                        0.02 0.035 0.245                                                                              0.465 0.08                                                                              0.845                                        Toothpaste F:                                                                        0.02 0.035 0.19 0.485 0.01                                                                              0.740                                        __________________________________________________________________________     VO Code* = Visual Observation Code                                       

                                      TABLE 9                                     __________________________________________________________________________    CONCENTRATION (WEIGHT %) OF OTHER COMPOUNDS DETECTED                          IN TOOTHPASTES BY GAS CHROMATOGRAPHY/MASS SPECTROSCOPY                                    Comp.                                                                             Comp.                                                                             Comp.                                                                             Comp.                                                                             Comp.                                                                             Comp.                                                                             Comp.                                                                             Comp.                                                                             Comp                                                                              Comp                                 Glycerin                                                                           1   2   3   4   5   6   7   8   9   10                            __________________________________________________________________________    Toothpaste A                                                                         21.62                                                                              0.01    0.025                                                                             0.025                                                                             0.085                                                                             0.275                                                                             0.115       0.07                          Toothpaste B                                                                         18.06            0.01                                                                              0.055                                                                             0.155   0.55                                                                              0.01                              Toothpaste C                                                                         9.52         0.02    0.095                                                                             0.175                                                                             0.11                                                                              0.06                                                                              0.03                              Toothpaste D                                                                         8.98 0.07                                                                              0.01                                                                              0.01    0.065                                                                             0.275   0.105                                                                             0.05                                                                              0.05                          Toothpaste E                                                                         21.67                                                                              0.05                                                                              0.01                                                                              0.05                                                                              0.025                                                                             0.01                                                                              0.28    0.13    0.08                          Toothpaste F                                                                         12.15                                                                              0.04                                                                              0.01                                                                              0.04    0.04                                                                              0.14    0.065   0.01                          __________________________________________________________________________     Compound (Comp.) Identifification                                             1 1HO-2-Propanone                                                             2 3Octanol                                                                    3 4Methyl-1-(1-methylethyl)cyclohexene                                        4 Pulegone                                                                    5 Dodecanol (isomer 1)                                                        6 Dodecanol (isomer 2)                                                        7 3Phenyl-2-propenal                                                          8 Dodecanol (isomer 3)                                                        9 Eugenol                                                                

The invention has been described in detail with particular reference topreferred embodiments thereof, but it will be understood that variationsand modifications can be effected within the spirit and scope of theinvention. Moreover, all patents, patent applications (published andunpublished, foreign or domestic), literature references or otherpublications noted above are incorporated herein by reference for anydisclosure pertinent to the practice of this invention.

We claim:
 1. A molded object prepared from a composition consistingessentially of a copolyester having an inherent viscosity of 0.4 to 1.1dL/g,wherein the acid component comprises repeat units from 90 to 40mole % terephthalic acid and from 10 to 60 mole % of one or moreadditional dibasic acids selected from the group consisting ofisophthalic acid, cyclohexanedicarboxylic acid, naphthalenedicarboxylicacid, diphenyldicarboxylic acid, and stilbenedicarboxylic acid; whereinthe glycol component comprises repeat units from1,4-cyclohexanedimethanol.
 2. The molded object of claim 1 wherein saidacid component comprises repeat units of 85 to 52 mole % terephthalicacid and 15 to 48 mole % of one or more of said additional dibasicacids.
 3. The molded object of claim 2 wherein said acid componentcomprises repeat units of 83 to 52 mole % terephthalic acid and 17 to 48mole % of one or more of said additional dibasic acids.
 4. The moldedobject of claim 1 wherein said one or more of said additional dibasicacids is isophthalic acid, cyclohexanedicarboxylic acid,naphthalenedicarboxylic acid or a mixture thereof.
 5. The molded objectof claim 4 wherein one or more of said additional dibasic acids isisophthalic acid.
 6. The molded object of claim 4 wherein one or more ofsaid additional dibasic acids is 1,3-cyclohexanedicarboxylic acid. 7.The molded object of claim 4 wherein one or more of said additionaldibasic acids is 1,4-cyclohexanedicarboxylic acid.
 8. The molded objectof claim 4 wherein one or more said additional dibasic acids isnaphthalenedicarboxylic acid.
 9. The molded object of claim 8 whereinsaid naphthalenedicarboxylic acid is selected from the group consistingof 2,6-naphthalenedicarboxylic acid, 2,7-naphthalenedicarboxylic acid,1,4-naphthalenedicarboxylic acid, and 1,5-naphthalenedicarboxylic acid.10. The molded object of claim 1 comprising up to 10 mole % of evenfurther additional dibasic acids.
 11. The molded object of claim 10wherein said even further additional dibasic acids are selected from oneor more of the group consisting of aromatic dicarboxylic acids having 8to 14 carbon atoms, aliphatic dicarboxylic acids having 4 to 12 carbonatoms, and cycloaliphatic dicarboxylic acids having 8 to 12 carbonatoms.
 12. The molded object of claim 11 wherein said even furtheradditional dibasic acids are selected from one or more of the groupconsisting of phthalic acid, cyclohexanediacetic acid, succinic acid,glutaric acid, adipic acid, azelaic acid and sebacic acid.
 13. Themolded object of claim 1 wherein said glycol component comprises 70 to100 mole % 1,4-cyclohexanedimethanol.
 14. The molded object of claim 13wherein said glycol component comprises 80 to 100 mole %1,4-cyclohexanedimethanol.
 15. The molded object of claim 14 whereinsaid glycol component comprises 85 to 100 mole %1,4-cyclohexanedimethanol.
 16. The molded object of claim 15 whereinsaid glycol component comprises 90 to 100 mole %1,4-cyclohexanedimethanol.
 17. The molded object of claim 16 whereinsaid glycol component comprises 95 to 100 mole %1,4-cyclohexanedimethanol.
 18. The molded object of claim 13 whereinsaid glycol component contains up to 30 mole % of one or more additionalaliphatic or alicyclic glycols.
 19. The molded object of claim 18wherein said one or more additional glycols is selected from the groupconsisting of ethylene glycol, diethylene glycol, triethylene glycol,propanediol, butanediol, pentanediol, hexanediol, neopentyl glycol andtetramethylcyclobutanediol.
 20. The molded object of claim 19 whereinsaid one or more additional glycols comprises ethylene glycol.
 21. Themolded object of claim 1 having a crystallization haze half-time ofgreater than 1 minute.
 22. The molded object of claim 1 having acrystallization haze half-time of greater than 3 minutes.
 23. The moldedobject of claim 21 which is visually clear for portions of said objecthaving a thickness of from 1 to 11.5 mm.
 24. The molded object of claim22 having a crystallization haze half-time of greater than 5 minutes.25. The molded object of claim 23 which is visually clear for portionsof said object having a thickness of from 5 to 11.5 mm.
 26. The moldedobject of claim 1 prepared from said copolyester having a diffusetransmittance value of less than about 60% as determined by ASTM MethodD1003.
 27. The molded object of claim 1 having improved stress crackingresistance as determined for test specimens which are 0.32 centimetersthick under a flexural load with 2.7% strain.
 28. The molded object ofclaim 27 wherein said molded object has improved stress crackingresistance as determined for test specimens which are 0.32 centimetersthick under a flexural load with 2.7% strain.
 29. The molded object ofclaim 26 wherein said molded object has improved stress crackingresistance as determined for test specimens which are 0.32 centimetersthick under a flexural load with 2.7% strain and which are contactedwith toothpaste solution comprising 0.6 weight % flavorant as determinedby gas chromatography.
 30. The molded object of claim 29 wherein saidtoothpaste solution comprises:(a) water and (b) a toothpaste comprising0.6 weight % mint oil.
 31. The molded object of claim 30 wherein saidmolded object is contacted with said toothpaste solution for 18 to 186hours.
 32. The molded object of claim 29 wherein said molded object iscontacted with said flavorant for 1 to 118 hours.
 33. The molded objectof claim 32 wherein said molded object is contacted with flavorant for 1to 6 hours.
 34. The molded object of claim 29 wherein said flavorant isselected from the group consisting of peppermint oil, spearmint oil,curly mint oil, anise oil, Japanese anise oil, caraway oil, eucalyptusoil, fennel oil, cinnamon oil, clove oil, geranium oil, sage oil,pimento oil, thyme oil, and majoram oil.
 35. The molded object of claim34 wherein said flavorant is selected from mint oil.
 36. The moldedobject of claim 35 wherein said mint oil comprises a component selectedfrom the group consisting of limonene, cineole, menthone, menthol, andcarvone.
 37. The molded object of claim 35 wherein said mint oilcomprises peppermint oil.
 38. The molded object of claim 29 wherein saidflavorant contains menthol.
 39. The molded object of claim 1 wherein thecomposition consists of the copolyester.